PKU patients on a relaxed diet may be at risk for micronutrient deficiencies.

OBJECTIVE: To investigate micronutrient supply in phenylketonuria (PKU) patients on a relaxed diet. SUBJECTS/METHODS: Sixty-seven patients (6-45 years) with a phenylalanine tolerance ≥ 600 mg/day were included in the study. From a 3-day diet record, protein supply as well as consumption of essential amino acids and several micronutrients were assessed and compared with the current recommendations and data for the healthy population. RESULTS: Protein supply and consumption of all essential amino acids were sufficient in all patients. Supply of micronutrients depended on dietary regime. Patients with a total protein supply of 120% or more of the recommended amount and at least 0.5 g protein per kg body weight from amino-acid mixture (AAM) were sufficiently supplied with all investigated micronutrients. All patients without AAM supplement showed severe micronutrient deficiencies in their diet records. CONCLUSION: PKU patients under a relaxed diet are at risk of an insufficient nutrient supply, if they have first no substitution with AAM, second a protein supply less than 0.5 g per kg body weight from AAM or third a total protein supply less than 120% of the recommendations. Therefore, close monitoring, specific dietary counseling and potential supplementation is mandatory to prevent micronutrient deficiencies in PKU patients.

Occupational adaptation: toward a holistic approach for contemporary practice, Part 2.

This paper introduces a practice model based on the occupational adaptation frame of reference (Schkade & Schultz, 1992). The occupational adaptation practice model emphasizes the creation of a therapeutic climate, the use of occupational activity, and the importance of relative mastery. Practice based on occupational adaptation differs from treatment that focuses on acquisition of functional skills because the practice model directs occupational therapy interventions toward the patient's internal processes and how such processes are facilitated to improve occupational functioning. The occupational adaptation practice model is holistic. The patient's occupational environments (as influenced by physical, social, and cultural properties) are as important as the patient's sensorimotor, cognitive, and psychosocial functioning and the patient's experience of personal limitations and potential is validated. The integration of these concepts drives the treatment process. Through a description of treatment with a variety of patients, this paper presents the model's diversity and illustrates the relationship between the concepts. The occupational adaptation practice model reflects the uniqueness of occupational therapy and integrates the profession's historical practice with contemporary interventions and methods.

Occupational adaptation: toward a holistic approach for contemporary practice, Part 1.

A theoretical perspective designed for clinical application and based on fundamental occupational therapy principles is offered. This perspective, the occupational adaptation frame of reference, is presented as an articulation of (a) a normal developmental process leading to competence in occupational functioning; (b) the process through which the benefits of occupational therapy occur; and (c) a perspective that promotes holistic practice. The person is viewed as operating occupationally through an idiosyncratic configuration of sensorimotor, cognitive, and psychosocial systems, all of which are inevitably involved in each occupational response. This occupational functioning is described as occurring through interaction of the person with a work, play and leisure, or selfcare context that has distinctive physical, social, and cultural properties (i.e., the occupational environment). Occupational adaptation is a perspective that can influence practice, education, and research.

Relationships between intracellular amino acid levels and protection against injury to isolated proximal tubules.

Metabolism and cellular levels of glycine, alanine, and other relevant amino acids in proximal tubules were studied during models of acute injury and protection by glycine. Freeze-clamped, normal rabbit renal cortex was very rich in glycine (66.8 nmol/mg protein) and glutamate and also had substantial levels of taurine, alanine, glutamine, serine, and aspartate. Isolated proximal tubules were severely depleted of all these amino acids (glycine, 2.1 nmol/mg protein). During 37 degrees C incubation in presence of alanine, tubules recovered only glutamate to a level approximating that in vivo (38.8 nmol/mg protein, 15.2 mM). Glycine added to medium at levels ranging from 0.25 to 2 mM was actively concentrated four- to sixfold by tubule cells. Two millimolar glycine potently protected tubules from lethal cell injury induced by hypoxia, antimycin A, or ouabain. Glycine levels of injured tubules rapidly equilibrated with medium, irrespective of whether glycine was loaded by preincubation or was added concomitantly with the injury maneuver. Metabolism of glycine during protection, assessed by changes in total levels, gas chromatography-mass spectroscopy determination of the fate of [13C]glycine, and redistribution of label from [3H]glycine was minimal. The data suggest that glycine plays an essential, constitutive role in maintenance of tubule cell structural integrity independently of common metabolic pathways. Intracellular amino acid content is sufficiently labile for depletion of structurally essential amino acids to potentially occur in a variety of settings, but, even with severe ATP depletion or Na+ pump inhibition, supplemental glycine is readily available to intracellular sites of action.

Cation transport in Escherichia coli. VII. Potassium requirement for phosphate uptake.

When Escherichia coli K-12 is grown in media containing limiting amounts of K, growth continues normally until all the extracellular K has been consumed. Thereafter the rates of growth, glucose consumption, and oxygen consumption decrease progressively, and the cell contents of K and P fall. These changes, referred to as K limitation, are all reversed by the addition of K. By specifically altering the ionic composition of the cells it was shown that these metabolic disturbances are not due to changes in the cell content of K or Na, but are directly related to the absence of K from the extracellular medium. The cell pool of inorganic P and the uptake of PO(4) from the medium are low in K-limited cells and are immediately stimulated by the addition of K, suggesting that the primary effect of K limitation is to inhibit PO(4) uptake. All the metabolic effects of K limitation can be attributed to inhibition of PO(4) uptake. The requirement of extracellular K for PO(4) uptake may be due to a coupling between the uptake of K and PO(4).